The purpose of this application is to better particularize the high efficiency infinitely variable-displacement fluid power transformer included with the wave energy converter (WEC) application, to claim it as a separate invention, as required in accordance with the rules of electronic filing when proceeding with an application-to-make-special to achieve accelerated-examination with the object to achieve final allowance within one year. The benefits of efficiency improvement is recited by the “Engineering Research Center for Compact and Efficient Fluid Power” group of universities funded by the National Science Foundation reports that a one percent improvement in the efficiency of exiting hydraulic energy use would result in a savings of $1 billion per year in the USA. The field of fluid power in which the invention applies is shown by analogy with an electric distribution system in FIG. 68.
Artisans of electronic filing will appreciate the speed of comprehension of figures with consistent margins and scale used in this application and in the companion WEC application, when drawings in pdf format are viewed full page size on a computer screen they become animated by rolling the mouse wheel, making it possible to instantly view effects of switching changes on fluid flow, such as for example in this application, when scrolling between power-stroke and return-stroke, or pressure-boost and pressure-reduce, in FIGS. 6 to 9. To meet the requirement to disclose the best mode of application of the invention, and the closest related art for transformer applications generally and including the WEC, the applicant devised a new form of expression, known herein as a multidimensional cube, and explained it with additional figures and description for the Class A, Class B, Class C transformers, and most recently published closest related art, in sets of FIGS. 46 to 49 Class A, 50 to 53 Class B, 54 to 57 Class C, and 60, 61 and 68, respectively. FIGS. 40 to 44 are more particularized expressions for comparing the inventive switching features for the claims section. The aforementioned multi-dimensional expressions (cubes) are formulated in high resolution vector graphics, at press quality, allowing for magnification to more than 15 times page size on the computer screen, for viewing the fine details of switching and fluid flows, and the polarity of fluid flow and shaft rotation.
The multi-dimensional cubes could be further particularized to include for the efficiency improvement of the transformer by sectionalizing the assembly of hydraulic cylinders below the WEC piston shown in FIG. 5, into groups with two sections as shown in FIGS. 36 and 37, and into groups with three sections as shown in FIG. 38.
Artisans will appreciate on perusing the drawings and description in the 2008 filing, that the inventor had possession of the claimed subject matter at the claimed priority time, 18 Jun. 2008, and that artisans generally could not have foreseen the same claimed subject matter in his earlier application, referenced here as CA 2,408,855, filed in Canada in 2002, published in 2004, and abandoned in June 2008, prior to any claims being accepted. This is apparent also on comparison with the recently published closest related art.
The inventive transformer relates to fluid power transmission systems for fast varying cyclic applications like ocean wave energy converters, hydraulic hybrid applications, and, more generally, to a wide range of vertical and horizontal translating and forward-reverse rotation applications. Fluid power transformers are known in hydraulic systems for converting or recovering energy of recurring motion to electric energy, and for boosting and reducing fluid pressure between different levels in common pressure rail (“CPR”) systems.
It is known that hydraulic power systems with linear and rotational actuation can operate in both motoring mode and regenerating mode, that of extending/retracting and forward/reverse rotation, and that these modes can be segregated into four quadrants, Q1 to Q4. It is also known that rotational actuation can be made electronically reversible in each of the quadrants. Fluid power flows from the CPR through the transformer to the actuator in motoring mode, and from the actuator through the transformer to the CPR in regeneration mode.
In U.S. Pat. No. 7,028,470 to Achten, the sequence chosen shows motion in four quadrants of angular speed and torque in FIG. 8, which it is reported is also convertible to fluid force and linear displacement, namely Qi and Qiv, for a single-acting cylinder with linear extending and linear retracting, respectively. It can be concluded, therefore, that Qiv is a regeneration mode with external force applied to retract the cylinder. Therefore, when including for double-acting cylinders, Qii must be a linear extending mode because of movement in the same direction as Qi, and Qiii must be a linear retracting mode because of movement in the same direction as Qiv. Therefore, it can be concluded that Qii is a regeneration mode and Qiii is a motoring mode. This quadrant by quadrant sequence of Achten is troublesome because it is difficult to visualize the connection of transformer to the actuator in a particular quadrant to visualize actuation and transformer fluid flow.
The quadrant sequence used in this application is particular to the new form of expression, with motoring on the right quadrants (Q1 and Q2), and regeneration on the left quadrants (Q3 and Q4), making it possible to visualize the overall functionality of the Class A and Class B transformers and linear and rotary actuators with their respective multi-dimensional cubes.
According to the invention there is provided a means for transmitting energy between a CPR and an actuator with the smoothness and flexibility of current art infinitely variable motors and pumps, and equally importantly, substantially more efficiently than prior art transformers. There is further provided a means for smoothly paralleling transformers and taking them out of service without fluid power interruption.
The parent invention or companion device, also known herein as the prime mover device, or actuator device, on which this application claims benefit of priority, is the application of the inventive transformer to a wave energy converter (WEC) where the benefits of the high efficiency fluid power transformer are shown to result in a smooth transfer of hydraulic energy to electric energy to a utility grid, with saved energy that would otherwise have been lost with less efficient prior art fluid transformation. It is shown herein that from 34% more to 42% more electric power can be generated by use of the inventive transformer in the fluid transmission pressure change range of 50% to 20%, respectively. In other words, the inventive fluid power transformer is shown to be substantially more efficient than prior art transformers in the whole range of 50% or less change in pressure between transmission sending end and receiving end, with energy savings in the more than 50% pressure change range tapering off from the aforementioned 34% savings, as well. One of the objectives in this application is to provide an efficient transformer of fixed and variable embodiments for a system with several common pressure rails CPRs where fluid can transfer efficiently among them. For example a manufacturer's warehouse filled with products piled high, designed especially for hydraulic-hybrid forklift trucks, could have peak periods of regeneration in early morning when loading outgoing highway trucks, and periods of motoring in early afternoon when unloading incoming trucks and restocking the warehouse.
The following publications describe a number of prior approaches to convert energy of recurring motion to other forms of usable energy, such as electric energy, including but not limited to applications to wave energy, and to other means of efficient fluid power transformation:                Burns: International Patent Publication No. WO 2004/0003380;        Burns: International Patent Publication No. WO 2007/019640;        Gardner: U.S. Pat. No. 6,256,985;        Kouns: U.S. Pat. No. 3,627,451;        Rexroth: U.S. Pat. No. 4,819,429;        Otremba et al: U.S. Pat. No. 5,568,766;        Achten: U.S. Pat. No. 6,116,138;        Fales: U.S. Pat. No. 6,854,268;        Achten: U.S. Pat. No. 7,028,470;        Cherney: U.S. Pat. No. 7,124,576;        Walker: U.S. Pat. No. 7,562,944;        Achten: EP2246566A2;        Stromotich: CA Patent Application No. 2,408,855 filed in 2002 and abandoned in June 2008.        